hi folks, i just changed the right side cam cover seals on my 99 xk8. started it up no more leaks. however after about 30 miles or so i detected a slight knocking noise and it seems to be coming from the intake. i used a stethoscope on and around the cam cover and it is definitely not coming from there it is a hollow sound so i dont think valve train or crank bearings are the issue. what are knock sensors? could that be the problem? any input would be appreciated thanx steve